by Bell H

Image for family history article Sometimes it really is all in the genes. Knowing your family's medical history can alert you to potential problems and help you take safety measures. As researchers discover new genetic markers, certain individuals and families may be identified as having a higher than average risk for a variety of diseases. When it comes to your health, the apple does not fall far from the tree. Knowing your family medical history may save your life or the lives of your children and grandchildren.

Certain types of cancers run in families. Sometimes it's because the family members have common risk factors, but in some cases it's because the family members share a genetic trait that is being passed down through the generations. Some cancers that are linked to family history include breast, ovarian, prostate, and colon cancer.

Conditions like heart disease, stroke, asthma, diabetes, arthritis, and Alzheimer disease also tend to run in families. You might not be affected just because someone else in your family was, but under certain circumstances your risk might be increased. Inherited risk involves complex interactions among several genes and your environment. Your behaviors—smoking, weight management, dealing with stress, heavy drinking, exposure to toxins—influence whether you'll get a disease.

Sleuthing Your Family Medical History

Your family medical history is valuable to you and to future generations of your family. Medical histories for your first-degree relatives are most important. First-degree relatives include:

  • Parents
  • Brothers and sisters
  • Children

You probably already know a lot of your family medical history. For the rest, talk to relatives. If you explain the good deed you are doing for the whole family, they may be more open to discussing dates of diagnoses and causes of death. Death certificates are available at your county records department for a reasonable cost. To request a medical record from a hospital or doctor, you must have written permission from the person whose record you want. If they are deceased, you must get written permission from the closest living relative.

How to Create a Family Medical Tree

Researching your family medical history is like genealogy. You can keep it simple or get completely carried away. Consider including the following information:

  • Date of birth
  • Date of death
  • Cause of death
  • Major illnesses or surgeries
  • Date when major illness was diagnosed

If you can, collect the same information about your second-degree relatives:

  • Grandparents
  • Aunts and uncles
  • Nieces and nephews
  • Grandchildren

As you build your family medical tree, remember these tips:

Get the Details

Be as specific as possible about cause of death and major illnesses. Knowing grandpa had cancer is a start. But what kind of cancer? At what age was he diagnosed? Did he develop a second cancer? Was it related to the first? Be wary of the cancer spread trap. Many cancers start in one organ but spread to another, often the brain, liver, lung, or bone. If you conclude that your relative had lung cancer when she really died of ovarian cancer that had spread to the lung, you will likely have misleading family history information. Unfortunately, sometimes it is hard or impossible to find out the true origins of a cancer.

Find out About Health Habits

Take it a step further if you would like. Include significant habits and any unusual physical characteristics. Grandma Nelson's dowager's hump may mean her daughter and granddaughter are at risk for osteoporosis. Uncle Fester's 3-pack-a-day habit—not heredity—may be why he died of cancer.

Organize the Information on Paper

A visual representation of your family medical tree can help you organize the information you collect. On the bottom of the tree, put your name, along with your sisters and brothers. On the row above, put your parents and their brothers and sisters. On the top row, put your grandparents. Put a square around each man and a circle around each woman. Leave enough room in each to summarize the information you've collected. Indicate marriages by connecting with lines.

What Does It All Mean?

Here are a few general guidelines for interpreting the medical information of your relatives:

  • The more generations an illness occurs in your family, the more at risk you are.
  • 2 or more first-degree relatives with the same or related cancers suggests an inherited risk. For example, if you have 2 first-degree relatives with ovarian cancer, you have a greater chance of getting it yourself. Keep in mind breast, ovarian, uterine, and colon cancers are genetically related.
  • The younger someone is when a disease develops, the more likely heredity played a role. If your mother or sister developed breast cancer before menopause, your lifetime risk is higher than it is for other women.
  • A disease that strikes 2 or more relatives at about the same age is likely to be strongly influenced by heredity.
  • Clustering of cases of the same disease on one side of the family more strongly suggests a genetic influence than if a similar number of cases are scattered on both sides of the family.

What If You Are at Risk?

If you suspect you are at risk for a disease, show your doctor your family medical history. Your doctor may suggest you undergo screening exams sooner than is normally recommended.

Genetic Counseling

Your doctor may refer you to a genetic counselor. Genetic counselors can talk to you about genetic testing and about banking your DNA.

DNA Banking

You can collect your DNA and save it for testing at a later date. Genetic tests are already available for many inherited diseases. Even if there is not a genetic test for your disease, there may be one in the future. Your sample may save the life of your grandchildren or great-grandchildren.

Banking your DNA is easy. You can purchase a kit and collect and store the samples yourself. You can store these samples in envelopes wherever you keep important documents. Or, you can deposit your sample with a commercial gene bank—for a fee—for indefinite storage.

Genetic testing is a complex matter. It does not offer 100% predictability. It may give you a peace of mind, but it also can be a source of significant anxiety for some people. Before deciding, weigh all the benefits and risks, and talk to your doctor or a genetic counselor. Ultimately, you have the final decision.


My Family Health Portrait—US Department of Health and Human Services 

National Human Genome Research Institute 


Health Canada 

Public Health Agency of Canada 


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